Automatic machine for washing laboratory ware



TIMER MOTOR y W57 c. J. SCHROEDER 3,336,925

AUTOMATIC MACHINE FOR WASHING LABORATORY WARE Filed April 8, 1965 2 Sheets-Sheet 1 SECOND FIRST SECOND THIRD WASH RI MS E DRAIN FILL VALVES HEATER SELECTOR INVENTOR. CARL J. SCHROEDER ATTORNEY y W67 c. J. SCHROEDER 3,316,925

AUTOMATIC MACHINE FOR WASHING LABORATORY WARE Filed April 8, 1965 2 Sheets-Sheet 2 3! PEG. 2

g 33 MFW TW RINSE WATER 3 SELECTOR SWITCH UNIT 35 F I50 8 38 5 a 37 g Lg T O c o E A Q o O F 30 S 23 I n I B 2- J LI/ L2 INVENTOR. CARL J. SCHROEDER ATTORNEY United States Patent 3,316,925 AUTOMATIC MACHINE FOR WASHING LABORATORY WARE Carl J. Schroeder, Burton, Ohio, assignor to The Chemical Rubber Company, Cleveland, Ohio, a corporation of Qhio Fiied Apr. 8, 1965, Ser. No. 446,516 2 Claims. (Cl. 134-58) This invention relates to an automatic machine [or washing laboratory ware.

More particularly, the invention relates to a machine for washing laboratory ware in accordance with an automatic, timed cycle which includes a wash stage followed by a plurality of rinse stages, and includes means providing a choice between a tap water rinse and a mineral-free water rinse for each of the rinse stages. (For purposes of this disclosure mineral-free water is intended to cover broadly demineralized water as well as water which is initially free of minerals.)

The nature of a given laboratory experiment will determine the extent to which the laboratory ware used must be free of mineral deposits. Laboratory ware which is washed and rinsed in tap water will, upon being dried, carry enough mineral deposits to interfere with many experiments. Accordingly, there is a need in automatic laboratory ware washing equipment for flexibility in the type of water which is made available during the rinse stages of the washing operation.

The machine of the present invention fills this need, by providing means for preselecting either tap water or mineral-free water for each rinse stage. Thus in atypical machine which has three rinse stages, one may select either tap water or mineral-free water for each of the three rinse stages. This means that a batch of laboratory ware may be rinsed three times in tap water, twice in tap water with a final rinse in mineral-free water, once in tap water with the second and third rinses in mineralfree water, or rinsed three times in mineral-free water.

This complete flexibility also permits the most economical use of the more expensive mineral-free water, as is consistent with the degree of mineral freeness required of the laboratory ware. Accordingly, where the requisite degree of mineral freeness can be met by using mineralfree water in only the final rinse, the cost saving of using tap water for the first two rinses'can be realized.

A better understanding of the invention may be had from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational View, with some parts broken away, showing the general arrangement of the laboratory ware washing machine in accordance with the invention;

FIG. 2 is a schematic wiring diagram illustrating the controls of the machine; 7

FIG. 3 is a chart illustrating the sequence of operations of the machine; and v FIG. 4 is a perspective view of the rinse water selector switch unit.

Referring to the drawings, which illustrate a preferred embodiment of the invention, FIG. 1 shows the general arrangement of a laboratory ware washing machine incorporating the features of the present invention. The machine includes a cabinet 10, mounted on a base 11 and having formed therein a washing chamber 12 including a sump 13. The area 14 below the washing chamber and sump provides enclosure for the drive motor 15 and motor driven pump 16 which recirculates water from the sump 13 through the rotary mounted spray head 17. Plumbing connections include a tap water supply line and a mineral-free water supply line (neither shown), a minrality of pairs of contact labeled A] inclusive.

3,316,925 Patented May 2, 1967 eral-free water pump unit 18 (FIG. 2) comprising a pump and motor, a mineral-free water fill valve 19, a tap-water fill valve 20, and a drain valve '21. The two fill valves and the drain valve are preferably of the solenoid-actuated type and in the case illustrated, are normally closed and open when the solenoid is energized.

As shown in FIGS. 1 and 2, the machine also incorporates a timer 22 which is operated by a timer motor 23 (FIG. 2 only). The timer is actuated to start a cycle of operation of the machine, and controls the energiz-ation of the fill and drain valve solenoids and of the main pump drive motor 15 to establish the desired sequence of operations. Details of the timer and its control of the sequence of operations will be explained in detail presently.

The preferred machine illustrated is of the front loading and unloading construction, having a door 24 hinged adjacent its lower edge, to swing forward and downward providing access to the washing chamber 12.

The washing chamber houses a lower rack 25 mounted to move from its position within the chamber, outward onto the surface of the lowered door 24, which in turn provides a convenient support for the rack during loading and unloading with laboratory ware. The rack is of the open mesh type which permits sprayed cleaning fluid from spray head 17 to pass through the rack and distribute effectively over the surfaces of the articles to be cleaned.

The washing chamber 12 also houses an upper rack 26 which is provided with a suitable mounting 27 accommodating movement of the rack outward to facilitate loading and unloading. When the rack is pulled outward, it is supported by the mounting 27.

A detergent dispenser 28 is mounted on inner panel 29 of door 24 where it is readily accessible for charging prior to use of the machine.

Referring to the schematic diagram of the control circuit shown in FIG. 2, power is supplied through the lines marked L1 and L2 which are connected to terminal block 30*. Timer 22 is shown in schematic fashion with a plu- It will be understood by those skilled in the art that'timer motor 23 operates to turn a plurality of cams (not shown) inside timer 22 which function to open and close the contacts 'A] in a predetermined, timed cycle, and this in turn (FIG. 2). This closes contacts A which act as a power input to the timer 22. At the same time contacts B are closed timer motor 23 is energized and as shown in FIG. 3, the timer motor remains in operation through the entire cycle of the machine.

Next, timer contacts I are closed which completes a circuit to the solenoid associated with tap water fill valve 20. Energizing the solenoid opens the normally closed valve 20 and begins to fill sump 13. While valve 20 is still open, timer contacts C are closed, completing a circuit to pump drive motor 15 through its starting relay 15a, thus activating pump 16. This causes water to circulate through spray head 17 and be sprayed over the articles in the washing chamber.

As seen in FIG. 3, tap water fill valve 20 closes during the early part of the first wash stage; this is accomplished by the opening of timer contacts J which de-energizes the solenoid associated with valve 20 permitting the valve to close.

The first wash stage is ended by the opening of timer contacts C which de-energizes pump motor 15 and stops pump 16. At this point the closing of timer contacts E energizes the solenoid associated with drain valve 21,

causing the normally closed valve to open and drain the sump of wash water. When the first wash stage water has been removed timer contacts E open, de-energizing the drain valve solenoid and closing the drain valve. At this point, timer contacts i and C are simultaneously 'closed thereby introducing a fresh charge of tap water through fill valve 20 and pumping the water through spray head 17. This starts the second wash stage.

After the programmed period of time, contacts C are opened, de-energizing pump motor 15 and stopping pump 16. Simultaneously, contacts E close, energizing the solenoid associated with drain valve 21, causing the drain, to open and drain the sump of wash water. When the second wash stage water has been removed, contacts E open, de-energizing the drain valve solenoid and closing the drain valve. -Now begins the rinse portion of the cycle.

Referring to the rinse'water selector switch unit shown in FIGS. 1 and 4, it will be seen that the unit comprises a face plate 32, and three rocker switches 33, 34 and 35. The face plate 32 is suitably marked to indicate which switch controls the first, second and third rinse stages, and which position of each switch will provide tap water (TW) and mineral-free water ('MFW).

At some time prior to the commencement of the rinse portion of the operating cycle (generally before the machine is started) the operator will manually select either tap water or mineral-free water for each rinse stage by appropriate manipulation of switches 33, 34 and 35. As shown in FIG. 4, tap water has been selected for the first and second rinse stages, and mineral-free water for the third rinse stage. The effects of these selections will now be shown in connection with FIGS. 2 and 3.

Referring to FIG. 2, the selection of tap water for the first and second rinse stages, joins the center and right hand contacts of switches 33 and 34; selection of mineralfree Water for the third stage joins the center and left hand contacts of switch 35. At the beginning of the first rinse stage, timer contacts G close, sending current through the center and right hand contacts of switch 33 and thence to the circuit containing the solenoid associated with fill valve 20 (by-passing open timer contacts I). Energizing the solenoid opens the normally closed valve 20 and fills sump 13 with tap water.

With the closing of contacts G, timer contacts C are closed, completing a circuit to pump drive motor 15 through its starting relay 15a, thus activating pump 16. This causes rinse water to circulate through spray head 17 and be sprayed over the articles in the washing chamber. While contacts C are still closed, contacts G open, de-energizing the solenoid associated with fill valve 20, thus closing the valve.

Thereafter contacts C open with the simultaneous closing of contacts E, whereby the spraying of water ceases, and the rinse water is drained away.

At the start of the second rinse stage, timer contacts E open closing drain valve 21, contacts C close activating pump motor 15, and contacts I close sending current through the center and right hand contacts of switch 34 and thence to the circuit containing the solenoid associated with fill valve 20 (by-passing open timer contacts J). IEnergizing the solenoid opens the normally closed valve 20 and fills sump 13 with tap water. The remainder of the second rinse stage proceeds identically as described for the first rinse stage.

At the start of the third rinse stage, contacts E open closing drain valve 21, contacts C close activating pump motor 15, and contacts F close with the following effect: recalling that mineral-free Water was selected for the third rinse stage and this selection joined the center and left hand contacts of switch 35, the closing of contacts F causes current to travel through the center and left hand contacts of switch 35 and thence to the circuit containing solenoid-activated mineral-free water fill valve 19 and t e motor of mineral-free water pump unit 18.

Activation of the solenoid associated with valve 19 opens the normally closed valve, supplying mineral-free water to pump unit 18 which then pumps the water into sump 13 of washing chamber 12. Since pump motor 15 was also activated at the start of the third rinse stage, the mineral-free water is coursed through pump 16 and circulated through spray head 17 and sprayed over the articles in the washing chamber.

It will be understood that the separate mineral-free water pump unit is not needed in installations where mineral-free Water is .available under sufiicient pressure to fill sump 13. In general, however, mineral-free water is available only under a low pressure hydrostatic head, in which case the pump unit is needed for a satisfactory filling operation.

Had mineral-free water been selected for the first rinse stage, the center and left hand contacts of switch 33 would have been joined, so that the closing of timer contacts G would have completed the circuit containing mineralfree water fill valve 19 .and pump unit 18. Similarly, had mineral-free water been selected for the second rinse stage, the center and left hand contacts of switch 34 would have been joined; so that the closing of timer contacts I would have completed the circuit containing mineralfree water fill valve 19 and pump unit 18.

It follows that had tap water been selected for the third rinse stage, the center and right hand contacts of switch 35 would have been joined so that the closing of timer contacts F would have completed the circuit containing tap water fill valve 20.

The third rinse stage proceeds as did the first and second, with the appropriate fill valve solenoid being deenergized during the period of activation of pump motor 15 and with the simultaneous deactivation of pump motor 15 and activation of the solenoid associated with drain valve 21.

At the close of the third r-inse stage, timer contacts E open, deactivating the solenoid associated with drain valve 21 closing the valve, and the drying stage is commenced by the closing of tirner contacts H, completing a circuit containing fan motor 36, thermostat 37 and heater 38. Hot air is circulated by a fan attached to fan motor 36, through the interior of washing chamber 12 to dry the articles therein. Thermostat 37 controls the temperature of heater 3% and prevents it from over-heating.

At the end of the drying stage timer contacts H open, de-energizing fan motor 36 and heater 38 and finally timer contacts B open de-energizing timer motor 23 and thereby shutting off the machine.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

I claim: 1. In a machine for washing laboratory ware in accordance with an automatic, timed cycle, which includes in sequence, a wash stage and a plurality of rinse stages,

a was-hing chamber, tap water fill control means connected to admit tap water to said chamber during said wash stage and during each of said plurality Olf rinse stages,

mineral-free water fill control means connected to admit mineral-free water to said chamber during each of said plurality of rinse stages, and

means for energizing one of the aforementioned fill control means during each of said plurality of rinse stages, comprising a timer connected to said control means for synchronizing the activation of the latter with the execution of each of said plurality of rinse stages, and a plurality of manually operable switches corresponding in number to said plurality of rinse 6 stages on the basis of one switch per rinse stage, a plurality of manually operable electrical switches coreach switch being connected to said timer, and [responding in number to said plurality of rinse stages operative to program the use of tap water and on the basis of one switch per rinse stage, each switch mineralafree water during only its correspondbeing electrically connected to said timer and operaing rinse stages 5 tive to program the use of tap water and mineral-free whereby one of said fill control means admits water to water during only its corresponding rinse stage, said chamber during each of said plurality of rinse stages whereby one of said fill valves admits water to said chamin accordance with the programming of said switches. her during each of said plurality of rinse stages in ac- 2. In a machine for washing laboratory ware in accordance with the programming of said switches. cordance with an automatic, timed cycle, which includes 10 in sequence, a wash stage and a plurality of rinse stages, Referellfies Cited y the Examine! a l t g fi t d fin I t d H t t UNITED STATES PATENTS an e ec rrca y opera e va ve o a m1 ap Wa er 0 said chamber during said Wash stage and during each 1581134 4/1926 Merseles 134 95 y 2,825,666 3/1958 Stoddard 134-58 X of said plurality of rinse stages, 15 3 125 105 3/1964 Geiger a second electrically operated fill valve to admit rmneral- 3,186,418 6/1965 Stem free Water to said chamber during each of said plurality of rinse stages WH a a power driven timer electrically connected to said fill CHARLES Y plmfary Exdmmer' valves to energize one of the same during each of 20 BLEUTGEiAs-Ylsmm' Exammersaid plurality of rinses, and 

1. IN A MACHINE FOR WASHING LABORATORY WARE IN ACCORDANCE WITH AN AUTOMATIC, TIMED CYCLE, WHICH INCLUDES IN SEQUENCE, A WASH STAGE AND A PLURALITY OF RINSE STAGES, A WASHING CHAMBER, TAP WATER FILL CONTROL MEANS CONNECTED TO ADMIT TAP WATER TO SAID CHAMBER DURING SAID WASH STAGE AND DURING EACH OF SAID PLURALITY OF RINSE STAGES, MINERAL-FREE WATER FILL CONTROL MEANS CONNECTED TO ADMIT MINERAL-FREE WATER TO SAID CHAMBER DURING EACH OF SAID PLURALITY OF RINSE STAGES, AND MEANS FOR ENERGIZING ONE OF THE AFOREMENTIONED FILL CONTROL MEANS DURING EACH OF SAID PLURALITY OF RINSE STAGES, COMPRISING A TIMER CONNECTED TO SAID CONTROL MEANS FOR SYNCHRONIZING THE ACTIVATION OF THE LATTER WITH THE EXECUTION OF EACH OF SAID PLURALITY OF RINSE STAGES, AND A PLURALITY OF MANUALLY OPERABLE SWITCHES CORRESPONDING IN NUMBER TO SAID PLURALITY OF RINSE STAGES ON THE BASIS OF ONE SWITCH PER RINSE STAGE, EACH SWITCH BEING CONNECTED TO SAID TIMER, AND OPERATIVE TO PROGRAM THE USE OF TAP WATER AND MINERAL-FREE WATER DURING ONLY ITS CORRESPONDING RINSE STAGES WHEREBY ONE OF SAID FILL CONTROL MEANS ADMITS WATER TO SAID CHAMBER DURING EACH OF SAID PLURALITY OF RINSE STAGES IN ACCORDANCE WITH THE PROGRAMMING OF SAID SWITCHES. 